The previously known systems referred to above provide a high level of security and permit a very high number of code combinations. Nevertheless, the methods being used for picking locks and for detecting master key codes, aiming at the unauthorized production of a master key, are steadily being developed and refined. Accordingly, there is a constant need for further improvement of the security level of lock and key systems, in particular to protect the coding being used in a particular lock and key system and to increase the security against unauthorised code detection and key making on the basis of one or more keys and associated locks.